The electric vehicle will become the trend of development of vehicles in the future due to characteristics of energy saving and environmental protection.
With the development of the vehicle, more and more attention has been paid to comfort inside a compartment. For the conventional vehicle with an internal combustion engine, the residual heat of the internal combustion engine and the heat of the engine exhaust may be used to heat the compartment, and the temperature of the circulating water of the vehicle with the internal combustion engine is generally greater than 80 degrees in the state of the vehicle normal traveling, which may basically meet the heating requirement of the compartment under various conditions. However, the power of the electric vehicle mainly comes from the electric motor, and the temperature of the circulating cooling water of the electric vehicle is only 50 degrees since the heat of the engine may not be used, which has difficulty in satisfying the heating requirement. On the other hand, the electric vehicle is provided therein with a plurality of heat generating components, for example, motor frequency converter, battery, etc., which are needed to be cooled by using respective cooling devices so as to ensure that the above components can work within the allowed temperature range.
In the prior art, in order that the temperature inside the compartment of the electric vehicle is maintained at a level that the human body feels comfortable, a variety of ways are used to provide heat to the compartment in the prior art: first, using an independent heat source, i.e. PTC, or fuels such as gasoline, kerosene and ethanol, to heat; second, using the residual heat of the a recovery equipment and auxiliary independent heat sources; and third, using a heat pump to ensure that the temperature inside the compartment is always maintained within a comfortable temperature range. On the other hand, in order to ensure that the heat generating components work within a normal temperature range, in the prior art, an air-cooled radiator, together with circulating water, is generally used to achieve the cooling of the above components.
However, among the various heating ways described above, if the independent heat source, such as PTC, is adopted to heat, a lot of battery energy will be consumed, resulting in a reduced travel distance of the vehicle; if fuels are used to heat, not only low heating efficiency but also environmental pollution may occur, and the load of the vehicle may be increased. On the other hand, independent radiators are needed to remove the heat of the heat generating components. In this way, the heat is not better used, and the heat generating components are poorly cooled under a high ambient temperature, and cannot work at the optimum temperature. Furthermore, as the environmental protection is increasingly concerned, new environmentally friendly refrigerant (e.g. R1234yf and R152a, etc.) will be gradually introduced in the future air conditioner of the electric vehicle. Such refrigerant is expensive and flammable, which may become problems existing in the present thermal system of the electric vehicle.
Therefore, at present, technical problems to be solved urgently by those skilled in the art are to improve the reasonableness of using the heat of the heat generating components of the electric vehicle and the effect of cooling the heat generating components, to improve the comfort of the compartment of the electric vehicle, to achieve the overall management of the thermal system of the electric vehicle, to reduce the charging amount of the refrigerant, and to prevent the refrigerant from entering into the compartment.